Heat the oil in a 10-inch skillet over medium-high heat. Add the beef and stir-fry until well browned.
Stir the soup, soy sauce, vinegar, garlic powder and red pepper, if desired, in the skillet and heat to a boil. Stir in the broccoli and cook until it's tender-crisp. Serve the beef mixture over the rice.
Ingredient Note: To make slicing easier, freeze the beef for 1 hour.
Serving Suggestions: Serve with glazed baby carrots: steam carrots with a touch of butter, brown sugar and cinnamon. For dessert serve chocolate ice cream.